Spark plug



Nov. 3, 1925{ 1,560,510

' L. HIRSCH SPARK PLUG Filed July 26, 1924 WITNESSES, 11v VEIYTOR,

' BY J v ATTORNEYS.

Zouzlr Iuzs'ch.,

Patented Nov. 3, 1925.

UNITED STAT LOUIS HIRSGI-I, 0F MESILLA PARK, NEVI MEXICO.

. SPARK PLUG.

Application filed July 26,

To all whom it may concern:

Be it known that I, Louis Hinson, a citi- Zen of the United States, anda resident of Mesilla Park, in the county of Dona Ana and State of NewMexico, have invented a new and Improved Spark Plug, of which thefollowing is a full, clear, and exact description.

This invention relates to improvements in spark plugs, an object of theinvention being to so construct a spark plug that the spark is visiblethrough a transparent portion of the plug, hence, a visible inspectionmay be had at all times to note whether or not the plug is functioningproperly.

A further object is to provide a spark plug in which the bore isprovided with a pair of insulated electrodes with terminals at the innerend of the core spaced apart forming a spark gap in line with atransparent plug fixedly located in the core so that the spark gap canbe observed without removing the plug.

A further object is to provide a plug of this character in which theelectrodes may be in a closed circuit, either a multiple are or series,and capable of a wide range of utility in connection with variouscircuits and controls which are not permissible with the ordinary typeof plug in which the circuit is grounded through the plug and engine.

With these and other objects in view, the invention consists in certainnovel features of construction and combinations and ar I rangements ofparts which will be more fully hereinafter described and pointed out inthe claim.

In the accompanying drawings-- Figure 1 is a view in longitudinalsection illustrating my improved spark plug;

Figure 2 is a view in transverse section on the line 22 of Figure 1.

1 represents the metal casing or jacket of my improved plug, which isexternally threaded at its lower end, as shown at 2, to screw into theengine cylinder, as is common in the art. This casing or jacket 1 ishollow and formed with an internal annular shoulder 3 and is internallyscrewthreaded at its upper end, as indicated at 4. 5 represents the coreof my improved plug, which is of porcelain or any other suitableinsulating material, and is positioned within the casing 1 and isprovided with an annular enlargement 6 between 1924-. Serial No.728,409.

which and the shoulder 3 a packing ring or gasket 7, of any approvedconstruction, may be located. 8 represents the nut which is screwed intothe threaded end 4 of car ing 1 with a packing ring or gasket 9 locatedbetween the inner end of the nut 8 and the enlargement 6 to securelyhold the core in the casing and prevent leakage.

The core 5 is made with three parallel longitudinal openings or bores10, 11 and 12, respectively. Electrodes 13 are located in the outerbores 10 and 12, and a transparent plug 14 is located in the centralbore 11 which is appreciably larger than the bores 10 and 12. Thistransparent plug 14 may be of glass or any other suitable transparentmaterial which may be baked. in the porcelain or secured in any otherapproved manner. The electrodes 13 are also mounted in the core so as torender the juncture gas-tight, and binding posts 15 are provided on theouter ends of the terminals of the electrodes 13 for the attach ment ofwires.

The inner end of the core 5 terminates preferably short of the inner endof the casing 1, and the inner ends of the clectrodes 13 are bentinwardly and extend toward each other, forming terminals 16 spaced apartto provide a spark gap which is located in alinement with the plug 141.Hence, while the engine is running, the spark can be observed throughthe trans parent plug.

In case it may be desirable to ground. one of the electrodes 13 in orderto enable the plug to be used in various electric circuits it is simplynecessary to provide a binding screw 17 fixed to the casing 1, and, whenthis plug is connected by a wire (not shown) with one of the bindingposts 15, my improved plug can be used in any ordinary grounded circuit.

While I refer to the plug 1 1 of transparent material it is to beunderstood that I use this term in its broadest possible sense toinclude any transparent or translucent material which will permit anobservation of the spark.

It is, of course, to be understood that the invention is not limited tothe particular materials employed or the precise manner of connectingthem, and various slight changes and alterations might be made in thegeneral form of the parts described without departing :From my inventionand hence I do not limit myself to the precise details set forth butconsider myself at liberty to make such slight changes and alterationsas fairly fall Within the spirit and scope of the appended claim.

I claim:

A spark plug, comprising a casing, an insulating core in the casing andof a length greater than the casing and projecting ap- 10 preciablyabove the upper end of the easing, said core having three parallelbores, a transparent core secured in the central bore and extendingthroughout the length of the core, and a pair of electrodes projectingthrough the other bores and having terminals at their inner ends spacedapart and located in line With the transparent core.

LOUIS HIRSCH.

